1. Field of the Invention
Embodiments of the present invention relate to methods, systems, and apparatuses for forming in situ gel pills or pigs to lift liquids from horizontal wells.
More particularly, embodiments of the present invention relate to methods, systems, and apparatuses for forming in situ gel pills or pigs to lift liquids from horizontal wells, where the methods include (1) injecting into a horizontal portion of a well a sufficient distance δ from a toe of the well a compositions capable of gelling under controlled conditions, (2) gelling the composition to form a gelled pill or pig, (3) using gas pressure from gas produced by the formation, from gas injected from the surface or a combination to gases from the formation or surface to push the pill or pig and accumulated liquids in front of the pill or pig through the horizontal portion of the well to the heal of the well, (4) breaking the gelled composition of the gelled pill or pig, and (5) lifting the composition and the liquids from a vertical portion of the well to facilitate gas production and reduce slugging. In certain, embodiments, the methods is repeated on a periodic, a semi-periodic, an intermittent, or an intermediate basis to keep the well in a desired non-slugging condition.
2. Description of the Related Art
To date there are a number of procedures to remove accumulated liquids (water, condensate, and/or oil) that accumulates in long substantially horizontal portion of a horizontal well. These methods include, for example, the use of velocity strings, foams, gas lifts, plunger lifts, hydraulic pistons, hydraulic jets, rod pumps, PC pumps, and ESP devices. However, all of these methods have definite disadvantages. The chemical foaming methods have difficulty assuring effective surfactant concentration across extended producing intervals. Gas lift methods become less effective as well pressures and flow velocities decline which often occurs rapidly in horizontal wells. Hydraulic jet methods and mechanical methods including rod pumps, progressing cavity pumps, electric submersible pumps, and hydraulic piston pumps all have single pump intakes which are inadequate in long horizontal runs which contain multiple liquid accumulation locations. Velocity strings are tuned to specific flow conditions and therefore must be replaced as the formation pressure and resulting flow velocities change.
Thus, there is a need in the art for methods, systems, and apparatuses that efficiently and effectively remove accumulated liquids from horizontal portions or sections of a well that is producing gas, where the methods are not based on gas lift, are not based on chemical foam, are not based on velocity, are not based on mechanical apparatuses, or are not based on hydraulic apparatuses.